Circuit breaker



Dec. 13, 1938. J. D. HILLIARD CIRCUIT BREAKER Filed Jan. 27, 1957 Patented Dec. 13, 1938 y UNITED STATES PATENT OFFIiE CIRCUIT BREAKER John D. Hilliard, Glens Falls, N. Y.

Application January 27, 1937, Serial N0. 122,498

7 Claims. (Cl. 20G- 150) This invention relates in general to circuit It is also an object of this invention to provide breakers and more particularly to circuit breaka circuit breaker in which failure of the presers of the fluid break type wherein the arc formed sure chamber due to parts weakened by producduring interruption of the circuit is extinguished tion operations in manufacture is avoided.

6 in oil or some similar insulating or arc extin- It is also an object of this invention to secure 5 guishing fluid. a throat opening or considerable width but of It is an object of this invention. to provide an small thickness so as to decrease the time reimproved circuit breaker of the above type quired for deionizing of the gas stream, thus wherein the arc is extinguished and the circuit to increase the eriiciency of interruption.

1U is interrupted in an improved and more efficient Objects and advantages other than those above lo manner. set forth will be apparent from following A further object of this invention is to provide description when read in connection with the aca circuit breaker of the above type with an arc- Companying drawing, in which:

u ing chamber having a throat opening extending Fig. 1 is a partial top section View of a circuit i u radially from the arc. breaker embodying the present invention taken n" It is further an object of the present inven- 0n the line I-I of Fig. 2; tion to provide in a circuit breaker of the above Fig. 2 is a front elevation View of the circuit type a pressure chamber supported from a curbreaker shown in Fig. l with part of the tank rent carrying stud member and provided with a removed; l0 throat opening extending radially from the stud Fig. 3 is a front elevation. detailed View oi one 20 in substantially all directions. of the pressure pots of the circuit breaker shown It is also an object of the present invention to in Figs. 1 and 2; provide in a circuit breaker of the above type a Fig. 4: is a top section view taken on the line snap acting moving contact assembly having a IV-IV of Fig. 3; and i5 rotary motion. Fig. 5 is a side view partly in section taken 25 It is also an object of the present invention to the line V-V of Fig. 4. provide a pressure chamber comprising a stack As shown in Figs. l and 2 the circuit breaker of laminations of insulating material with a of the present invention is provided with a tank means for spacing one part of the stack from 6 and a cover 'i through which insulating bush- 230 another part thereof to thereby form a throat ings 8 extend and carry the circuit breaker stud 9. 30 opening extending radially in a plane at sub- In order to fully utilize the advantages of: a movstantially a right angle to the stack of lamina ing Contact structure having a rotary motion tions. rather than a rectilinear motion, a simple 1 It is a further object of the present invention sure chamber construction is provided which 2.25 to provide a pressure chamber formed of a stack consists generally in a stack l@ of insulating 35 or stacks of insulating laminations held under laminations each of which has a substantial compression by a stud passing through the chamerture therein, whereby the stack forms the walls ber. of the pressure chamber. The chamber may be It is also an object of the present invention to closed at the end by a plate of insulation or by to provide .in a circuit breaker of the above type a second stack of laminations i! which is spaced 40 a pressure chamber which is simply and easily from the stack I0 by means of spacers to formed of laminations of insulation but kwhich is form another wall of the pressure chamber and rugged in construction. to provide for a throat opening which may be It is also an object of the present invention to any desired width from a narrow slot to substan- Al5 provide a method of and means for forming a tially 360 in extent. In utilizing the rotary mo- 45 pressure chamber with side walls of insulating tion of the moving Contact member, advantage is material, whereby a hoop tension is the only taken of the fact that the energy necessary to tensile stress applied to the said side walls duraccelerate a given mass to a given speed in roing circuit interruption. tary motion is much less 'than that of a conlo It is also an object of the present invention to tact member of the same mass having rectilinear 50 provide a method of and means for constructing motion and therefore the time of arcing is cora pressure chamber so that no stress beyond the respondingly short. This decreased energy of elastic limit of the insulating material used will acceleration is due to the small radius of gyrabe applied to thcstructure in the process of tion of the rotating mass as compared with the t5 manufacture. rectilinear motion of the mass of the ordinary 55 circuit breaker operating member, that is, for a given mass, the movement of inertia is much less than the momentum. In other words, the rotating operation of the moving Contact member and attached mechanism results in a given accelerating force producing a greater lineal acceleration of the moving arcing tip than if the same force is applied to the same mass but with rectilinear acceleration, and this provides a shorter arcing period, less gas generation, less oil dissociated, less carbon in the oil and therefore greater interrupting and maintenance eiciency. By using a rotary motion, the present construction provides a very simple method of forming a pressure chamber provided with a throat member of the extent desired, while at the same time due to the fact that the insulating laminations are held in compression the construction is very rugged.

The stack of laminations I0 is formed of disks having large apertures therein whereby the stack forms the walls of the pressure chamber. The bottom disks of the stack i0 may be cut shorter on one side thereof to form the throat opening as shown more clearly in Fig. 5. The lower stack of laminations II are formed to include a screw threaded member so that by turning both stacks of laminations, the entire assembly may be tightened on. the stud 9. The stud 9 is insulated in the pressure chamber by the member I1. The member in the stack II may be a nut or similar separate member or the stack itself may be threaded. The lower stack of laminations II is spaced from the upper stack as by means of insulatingr spacers l2, thereby providing the radial throat opening extending in all directions at right angles to the stack. The upper laminations of the lower stack I I are cut oi on one side similar to the lower laminations of the stack II) to form the throat 26. Openings 2l and 31 are provided through the walls of the lower stack II to form shunt vents, the openings 31 providing an expulsion port action, which greatly decreases the chamber pressure for a given quantity of gas generated, thereby increasing the interrupting capacity of the breaker.

The term throat or throat opening as used herein comprises an opening in a wall of the pressure chamber extending in a given plane substantially the entire perimeter thereof, such opening including the path through which the movable contact is operable to draw an arc and through which such arc may be drawn by the movable contact substantiallv in the plane of the opening.

In the preferred form of the invention the laminations i i are consolidated by heat and pressure to form a more stable and rugged construction. The laminatlons II are each impregnated with ."akelite or equivalent material and then stacked desired and the stacks put under pressure while heat is applied. In this manner a solid body of great strength is obtained when the stack has cooled, voids in the material are eliminated and water absorbtion decreased. This method avoids stressing the material beyond its elastic limit during construction of the chamber, as is the case where material is rolled into cylindrical form and then pressed into special shapes and then again pressing and heat polymerizing the prepressed section. In the ring construction initial fracture due to the pressing is completely avoided, resulting in a structiue that has a uniform strength. In the present invention, however, the rolled wall or the plastic molded construction may be used.

The snap acting moving contact assembly which operates with a rotary motion is supported from the cover member 1 which is provided with an upstanding boss 24 and a depending insulating member serving as bearings for the operating rod 23 of insulating material which extends therethrough.

The bridging member 21 is loosely mounted on the rod 23, the extension 35 providing a bearing whereby the member 21 may rotate on the rod 23 relative thereto. A member 39 is rigidly connected to the rod 23 for rotation therewith as by a pin 36 through the extension 35a. Member 39 is operably connected to the bridging member 21 through springs 28, pins 32 and stop members 33 rigidly mounted on member 39 and provided with bent over portions 34. Portions 34 engage bridging member 21 after a predetermined movement of member 39 against the biasing force of springs 28. A nut 26, acting in conjunction with the operating rod shoulder 38, holds the operating assembly in position.

The fixed contacts I8 are provided with pigtails I3 connected to the conducting stud 9 by nuts I4. The movable contacts I9 are held in the closed position shown in Fig, l by the friction of the fixed contacts I8. In the operation of the circuit breaker, a rotating movement is applied to the operating rod 23 and thereby to member 39, which movement tends to stretch springs 28 until the bent over ends 34 contact the bridging member. At such point the moving contacts I9 are forceably pulled from the xed contacts I8 with a snap action due to release of energy stored in springs 28. An arc is thereby drawn which, due to the pressure in the pressure chamber, the short term of arcing, the deionizing action of the throat 20 and due to the fact that the throat extends in all directions from the arc, is easily and rapidly extinguished.

'Ihe provision of a throat member extending radially in all directions has a function other than that of aiding in extinguishing the arc. Due to the construction disclosed the blast from the pressure chamber is substantially a balanced blast, that is, one in which there is no resultant bending moment applied to the bushing supporting the pressure chamber. In prior art construction especially where the natural period of vibration of the chamber may synchronize with the period of the circuit. the bending moment due to the vibration is the cause of many bushing failures. Due to the balanced construction shown this disadvantage is avoided.

Although but one embodiment of the present invention has been illustrated and described it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

l. In combination. a casing containing arc extinguishing huid, insulating bushing extending through said casing, a pressure chamber supported by said bushing in said fluid provided with an opening in the wall thereof extending substantially the entire perimeter of said wall in a given plane, a first contact supported in said pressure chamber, and a second contact movable in substantially said given plane through said opening and cooperable with said first contact to draw an arc.

2. In a circuit breaker, a tank containing arc extinguishing fluid. a conducting stud extending through said tank in insulated relation thereto,

a. stack of disks surrounding said stud in said uid and provided with substantial apertures therein forming Walls of a pressure chamber, a second stack of disks substantially Without apertures therein and supported on said stud to form another Wall of said pressure chamber, means for spacing said second stack from said rst stack to provide a throat opening therebetween substantially 360 in extent and at an angle to said stud, a rst contact in said pressure chamber, and a second contact movable parallel to said disks through said throat opening to draw an arc With said first contact.

3. In combination, a casing containing arc extinguishing fluid, a current conducting stud eX- tending through said casing in insulated relation thereto, and a pressure chamber supported by said stud in said fluid comprising laminations of insulation held under compression by said stud.

4. In combination, a casing containing arc extinguishing fluid, a current conducting stud extending through said casing in insulated relation thereto, a pressure chamber supported by said stud in said liquid comprising a plurality of stacks of insulation members spaced apart to form a throat opening substantially perpendicular to said stud, a iixed contact in said pressure chamber, a Contact movable through said throat opening in a plane parallel to said insulation members and cooperable With said fixed contact to draw an arc in said chamber, and means including said xed contact for imparting a snap action to said movable contact.

5. In combination, a casing containing are extinguishing uid, a current conducting stud extending through said casing in insulated relation thereto, a pressure chamber supported by said stud in said fluid and provided With a throat opening extending radially from said stud in a plane substantially perpendicular to said stud, and means for insulating said stud adjacent said throat opening.

6. In combination, a casing containing arc extinguishing fluid, an insulating bushing extending through said casing, a pressure chamber sup,- ported by said bushing in said iluid and provided with an opening in the wall thereof extending substantially the entire perimeter of said wall in a given plane, a first contact supported in said pressure chamber, a second Contact movable in substantially said given plane through said opening and cooperable With said rst contact to draw an arc, and an expulsion port in said pressure chamber adjacent said xed contact.

'7. In combination, a casing containing arc extinguishing fluid, a current conducting stud extending through said casing in insulating relation thereto, a pressure chamber built up of rings of insulating material spaced apart to form a throat opening and said rings held under compression by said stud, a stationary contact member in said chamber, a movable cooperating contact member, means for supporting said chamber and contact in electrical connection with said current conducting stud, means for separating said contact members to interrupt the electrical circuit.

JOHN D. HILLIARD. 

